The present invention relates to expert systems and particularly to a method of generating the rules therefor.
Expert systems as heretofore available have employed a technique known as knowledge engineering to formulate groups of rules for the solution of problems. The rules may be presented to the user by means of a series of questions which require observation by the user and input by the user of answers to the questions. The expert system will thereupon supply the user with a conclusion or conclusions in accordance with the set of rules. Expert systems have heretofore been employed in fields such as medical diagnosis for logically indicating a patient's status in accordance with a large number of observations, and would also be advantageously employed in the repair of various kinds of apparatus. The rules comprising the expert system are typically constructed by so-called knowledge engineers who interview experts in the field in order to derive the body of rules which captures the required expertise.
The human "knowledge engineer" usually builds a large collection of rules which conform to a predetermined rule structure required by the expert system. Another approach which goes a little farther towards reducing the costs of expert system development is to define rule structures within a particular structural form with reference to domain-specific terms which may be referred to as the task ontology. This simplifies the process of rule acquisition, since some decisions about control structures do not need to be made. The drawbacks of this approach are that a knowledge engineer in still required to acquire the task ontology for the form being utilized and to conform the expert knowledge into the specific rule form.